CVE-2018-20028 in Contao
Summary
by MITRE
Contao 3.x before 3.5.37, 4.4.x before 4.4.31 and 4.6.x before 4.6.11 has Incorrect Access Control.
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Analysis
by VulDB Data Team • 05/30/2020
This vulnerability affects Contao content management systems across multiple versions including 3.x before 3.5.37, 4.4.x before 4.4.31, and 4.6.x before 4.6.11, representing a critical access control flaw that allows unauthorized users to gain elevated privileges and access restricted administrative functions. The vulnerability stems from improper validation of user permissions within the application's authentication and authorization mechanisms, creating a path for privilege escalation attacks. This flaw specifically enables authenticated users with limited access rights to bypass security controls and execute administrative operations that should be restricted to authorized personnel only.
The technical implementation of this access control weakness manifests in the application's failure to properly verify user roles and permissions when processing requests for administrative functions. Attackers can exploit this by manipulating request parameters or leveraging existing user sessions to access backend interfaces, modify content, or perform system-level operations. The vulnerability is classified under CWE-285, which addresses improper authorization issues in software systems, specifically targeting the lack of proper access control validation. This weakness creates a direct pathway for attackers to escalate privileges from standard user accounts to administrator accounts, fundamentally compromising the application's security model.
The operational impact of this vulnerability is severe as it undermines the core security architecture of Contao installations, potentially allowing attackers to completely compromise websites and web applications. Organizations running affected versions face risks of data breaches, content tampering, unauthorized system modifications, and potential complete system takeover. The vulnerability affects the integrity and confidentiality of web applications, as unauthorized users can access sensitive administrative features and potentially exfiltrate data or modify critical system components. This flaw particularly impacts organizations relying on Contao for content management, as it provides attackers with direct access to content management interfaces and administrative controls.
Mitigation strategies for this vulnerability include immediate patching of affected Contao installations to the latest supported versions, which contain proper access control implementations and authorization checks. Organizations should also implement network segmentation to limit access to administrative interfaces, enforce strong authentication mechanisms including multi-factor authentication, and conduct regular security assessments of their web applications. Additionally, monitoring for suspicious access patterns and implementing web application firewalls can help detect and prevent exploitation attempts. The remediation process should include comprehensive testing to ensure that access controls function correctly after patching, and organizations should review their user permission configurations to minimize the impact of potential privilege escalation attacks. Security teams should also consider implementing principle of least privilege access controls and regular security audits to maintain robust protection against similar access control vulnerabilities.